According to a known stator of a rotary electrical machine, disclosed in, for example, JP4073705B, the stator is formed in a manner where a plurality of split cores, around each of which a coil is wound, is held to form a ring shape. End portions of the coil are respectively attached to a low voltage side terminal and a high voltage side terminal, which are respectively attached to insulators, having laminated steel plates.
The insulator is formed with groove portions, each of which is configured by a pair of vertical walls, at an inner end portion and an outer end portion of the insulator, respectively, in a radial direction of the stator. The groove portions, formed at the insulators of the adjacent split cores, are connected to each other, and thereby being formed so as to extend along an entire circumference at an inner end portion and an outer end portion of the stator in the radial direction thereof. The high voltage side terminal and the low voltage side terminal, each of which is connected to the end portions of the coil, are attached to the corresponding grooves of the insulator, and in such a state, the grooves are filled with an insulating resin material. Accordingly, low voltage side end portions of the coils of the split cores are integrated, and electricity may be applied to high voltage side end portions of the coils of the split cores in order to drive a rotor, which is provided at a radially inner side of the stator.
According to the stator disclosed in JP4073705B, the resin material is injected into the grooves, which are respectively formed at the inner end portion and the outer end portion of the stator in the radial direction thereof so as to extend along the entire circumference. Therefore, an amount of the insulating resin material, used for the filling, may increase, and a cost required for manufacturing the stator may increase. Further, the increase of the amount of the resin material may result in a restriction on a filling device and on a filling manner, such as a filling speed and a filling pressure. Accordingly, the cost may further increase.
Furthermore, it may be difficult to fill a detailed portion with the resin material because a portion to be filled with the resin material extends for a wide range. Accordingly, a portion where a filling of the resin material is deteriorated may be generated. In a case where the deterioration of the filling of the resin material occurs, the end portions of the coil may not be insulated sufficiently, and as a result the rotary electrical machine may not be operated appropriately.
A need thus exists for a stator of a rotary electrical machine, which is not susceptible to the drawback mentioned above.